The next-generation communication network will be primarily based on the 5G networks, with multiple wireless Radio Access Technologies (RATs) coexisting. The factors influencing user experience are complex and diverse, making it difficult for any single wireless technology to meet all user needs. Most existing network selection algorithms focus on either the user side or the network side, leading to the problem of network load imbalance. Therefore, this paper proposes a MultiAttribute Synergetic Decision (MASD) algorithm for 5G integrated heterogeneous wireless network. First, implement the pre-filtering of the candidate network set. Taking into account the diversity of user services, this algorithm focuses on Quality of Service (QoS), user preferences, and network load. Analytic Hierarchy Process (AHP) and Standard Deviation (SD) are used to calculate the weights of each attribute. Based on the synergetic theory, the entropy value of the candidate network system is obtained. Simulation results demonstrate that this algorithm effectively coordinates various factors to select the most suitable network for access. It reduces unnecessary handovers, avoids the ping-pong effect, and achieves load balancing to a certain extent. © (2023), (Electromagnetics Academy). All Rights Reserved.